The question as to whether some objects are possible worlds that have an initial segment in common, i.e. so that their fusion is a temporal tree whose branches are possible worlds, arises both for those who hold that our universe has the structure of a temporal tree and for those who hold that what there is includes concrete universes of every possible variety. The notion of “possible world” employed in the question is seen to be the notion of an object (...) of a kind such that objects of that kind play a certain theoretical role. Lewis’s discussion of the question is thereby clarified but is nevertheless inadequate; his negative answer is correct but even from his combinatorialist viewpoint the rationale he provides for this answer is misguided. I explain why the combinatorialist advocate of concrete plenitude should hold that no object is a tree of possible worlds. Then I explain that for a different reason the nomic essentialist advocate of concrete plenitude should hold this much too. (shrink)

For various reasons several authors have enriched classical first order syntax by adding a predicate abstraction operator. “Conservatives” have done so without disturbing the syntax of the formal quantifiers but “revisionists” have argued that predicate abstraction motivates the universal quantifier’s re-classification from an expression that combines with a variable to yield a sentence from a sentence, to an expression that combines with a one-place predicate to yield a sentence. My main aim is to advance the cause of predicate abstraction while (...) cautioning against revisionism. In so doing, however, I shall pursue a secondary aim by conveying mixed blessings to those who hold the view that in the logical sense of “existence” some existing object is such as to exist contingently. Advocates of this view must concede Williamson’s recent contention that the domain of unrestricted objectual quantification could not have been narrower than it is actually, but predicate abstraction affords them some hope of accommodating this concession. (shrink)

PaceZagzebski, there is no route from the value of knowledge to a non–reliabilist virtue–theoretic epistemology. Her discussion of the value problem is marred by an uncritical and confused employment of the notion of a “state” of knowledge, an uncritical acceptance of a “knowledge–belief” identity thesis, and an incoherent presumption that the widely held thought that knowledge is more valuable than true belief amounts to the view that knowledge is a state of true belief having an intrinsic property which a state (...) of ‘mere” true belief lacks. Her arguments against a “machine–product” conception of knowledge are undermined by these flaws, while the alternative “agent–act” model she recommends is unattractive, at odds with the knowledge–belief identity thesis she favours, and no solution to the problem of the value of knowledge she poses. I end with the observation that her version of virtue–theoretic epistemology points in the direction of cognitive decision–theoretic norms, and I briefly discuss the bearing of this fact upon her viewpoint. (shrink)

[Philip Percival] I aim to illuminate foundational epistemological issues by reflecting on 'epistemic consequentialism'-the epistemic analogue of ethical consequentialism. Epistemic consequentialism employs a concept of cognitive value playing a role in epistemic norms governing belief-like states that is analogous to the role goodness plays in act-governing moral norms. A distinction between 'direct' and 'indirect' versions of epistemic consequentialism is held to be as important as the familiar ethical distinction on which it is based. These versions are illustrated, respectively, by cognitive (...) decision-theory and reliabilism. Cognitive decision-theory is defended, and various conceptual issues concerning it explored. A simple dilemma suggests that epistemic consequentialism has radical consequences. /// [Robert Stalnaker] After reviewing the general ideas of the consequentialist framework, I take a critical look at two of the epistemic consequentialist projects that Philip Percival considers in his paper: the first assumes that there is a notion of acceptance that contrasts with belief and that can be evaluated by its expected epistemic utility. The second uses epis utility to evaluate beliefs and partial beliefs themselves, as well as actions, such as gathering information in the course of an inquiry. I express scepticism about the notion of acceptance required for the first project, and argue that the second kind of project can be fruitful only with a richer notion of epistemic utility than has yet been developed. (shrink)

In a brief passage, David Lewis derives from quantum-theory a dilemma regarding the explanation of chance events which he tries to solve by first distinguishing plain from contrastive why-questions have answers. His brevity warrants elaboration and critique. I endorse his derivation, but I make a structural objection to his solution. Once a further distinction is drawn between different kinds of contrastive why-question, his solution can be modified and refined so as to go some way to meeting this objection. However, it (...) cannot resist a deeper objection to the effect that chance events can be given contrastive explanations after all. The alternative solution to the dilemma that I recommend holds Lewis's conception of the 'essence of chance' to be illusory. (shrink)

In a Postscript, David Lewis tries to extend results obtained in his "Time's Arrow and Counterfactual Dependence" from the deterministic case to the indeterministic one. In particular, he claims that under the supposition that the actual world is indeterministic, the truth of the counterfactual 'If Nixon had pressed the button, there would have been a nuclear holocaust' is reconciled with his truth conditions for counterfactual conditionals by a certain refinement of his earlier treatment. Sections II and III explain why his (...) claim is mistaken. Section IV remarks why his matters. (shrink)

Quantum mechanics gives us reason to think both that the world is indeterministic, and that there are irreducibly statistical laws governing objectively chancy processes. Lewis notes that this raises a two-horned dilemma between two options deemed unacceptable: severely curtail our explanatory practices with respect to macro events, or revise our conception of the essence of chance. He maintains, however, that we can escape this dilemma by making a distinction between ‘plain’ why-questions of the simple form ‘Why did D occur?’ and (...) ‘contrastive’ why-questions of the more complex form ‘Why did E occur rather than E*?’ I will argue that even if a chance event receives a nontrivial explanation, there is still a sense in which it happens for no reason if there is a time prior to its occurrence at which the change of its happening when it does is fixed. (shrink)

This paper is in three sections. In the first I describe and illustrate three uses of indices of truth in semantics. The way I illustrate this classification is not completely uncontroversial, but I expect that my intuitions on this matter are generally shared. In the second section I broach a question which is central to the metaphysics of time, namely: how should certain temporal indices of truth - times - be fitted within this classificatory scheme? I sketch three proposals as (...) to how this might be done, and show how they constitute different metaphysical conceptions of the nature of time. Finally, in the third section I turn to a specific problem with the classification of times (as indices of truth) I call 'non-indexical'. Mellor (1981) thinks this problem insoluble, and argues that it shows this classification to be absurd. However, by appealing to the modal analogues of the issues involved, I first show that Mellor's argument is question- begging, and then go on to show how the non-indexical classification of times might undermine the presuppositions on which his argument rests. The paper attempts to contribute to a discussion of the question raised in section II, not to provide a definitive answer to it. (shrink)